WebSite: Nicola's content

[Riccardo Mottola]

Hi all,

as discussed during the GNUStep meeting, a Nicola's resources were 
partially missing.

I was able to retrieve from web archive the JIGS documentation and 
website. I needed some cleanup since WA injects JS code and alters all 
links, but I think it is fine now.

https://home.gnustep.org/jigs/index.html

Also Nicola's tutorials were apparently missing, yet most were present 
but the links were broken.
I kept the original page: https://home.gnustep.org/nicola/Tutorials/

But integrated them in the Documentation page where they are directly 
accessible.
https://home.gnustep.org/developers/documentation.html#minitutorials



Integration in the main website can be improved, but for now everything 
is salvaged and accessible.

Riccardo